<template>
  <div>
    <input v-model.number="num1" />
    <input v-model.number="num2" />
    <div>两个数之和为{{ result }}</div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      num1: 0,
      num2: 0,
      result: 0,
    }
  },
  methods: {
    sum (){
      this.result = this.num1 + this.num2
    }
  },
  // mounted:{
  //   result(){
  //     return this.num1 + this.num2
  //   }
  // },
  watch: {
    num1(){
      // this.num1 = newvalue
      // this.result = this.num1 + this.num2
      this.sum()
    },
    num2(){
      // this.num2 = newvalue
      // this.result = this.num1 + this.num2
      this.sum()
    }
    
  },
}
</script>

<style>

</style>